The invention is in the field of starch hydrolysates, in particular maltodextrins and other malto-oligosaccharides. More particularly, the invention relates to modification of such starch hydrolysates to impart improved characteristics.
Starch hydrolysate products are commonly spray dried, providing fine particle products which have relatively poor flow and bulk handling properties. Under humid conditions, these products will pick up moisture, become sticky, and form into large agglomerates or even solubilize into a sticky mass. They are not suitable for bulk shipping. In particular, when the starch hydrolysate is intended as an animal feed, in particular, a poultry feed, the stickiness that develops upon exposure to ambient moisture can plug handling equipment, and can prevent the animal feed from being transportable in normal process conveying equipment, such as bulk bins and auger conveyors. In particular, compressive forces at the discharge location of a bulk bin can cause sticky starch hydrolysate particles to compress and to form a solid, unitary mass.
The prior art has provided controlled agglomeration techniques, which provide products that can be handled in bulk and provide improved flow. However, agglomerated products have a relatively low bulk density, which often is undesirable. Moreover, compaction of dried starch hydrolysates can provide a more dense, free-flowing product. In U.S. Pat. Nos. 4,810,307 and 4,954,178, particles of starting material are blended with a volatile liquid other than water, and the resulting blend is compacted. The volatile liquids required by the processes disclosed in these patents are undesirable as they are released and must be dealt with via expensive measures.
It is a general object to provide a method for preparing a starch hydrolysate product that has reduced tendency to become sticky. Another general object is to provide such a starch hydrolysate.
It has now been found that starch hydrolysates can be compacted without an added volatile liquid to form a compacted product that has a relatively reduced tendency to become sticky in the presence of ambient moisture. Generally, the converted product further will have a reduced tendency to become compressed, and thus when subjected to pressures in bulk handling, the product will have a reduced tendency to form a unitary mass. The invention generally contemplates compaction, preferably roller compaction, of a starch hydrolysate. In certain embodiments, the starch hydrolysate is compacted without any added liquid, and in other embodiments, a liquid may be used, but the hydrolysate is compacted without any added liquid that is more volatile than water. Other means of compacting the starch hydrolysate include pellet milling and extrusion.
The resulting compacted starch hydrolysate exhibits improved bulk handling characteristics and a reduced tendency to become sticky if exposed to moisture during humid storage. The invention offers product with potential uses in animal feed applications such as for poultry and swine and in food applications where bulk handling is a necessity. The starch hydrolysate used in such applications preferably is a maltodextrin or syrup solid (e.g., a corn syrup solid).
The invention finds particular applicability in the field of poultry feeds, in particular, specialty, high carbohydrate feeds. In accordance with this aspect of the invention, a poultry feed is prepared from a starch hydrolysate, optionally with an additional poultry nutrient, by compacting the starch hydrolysate or nutrient/hydrolyzate blend under sufficient compaction pressure to provide a compacted product that has a relatively reduced tendency to become sticky in the presence of ambient moisture. The poultry feed thus prepared can be more readily transported, and will have a greater tendency to remain in the form of particles of a size suitable for feeding to a poultry bird. The hydrolysate also will have a reduced tendency to become compressed. The compacted product thus is particularly suitable for transport in bulk.
The invention contemplates the modification of a starch hydrolysate via compaction, or the modification of a blend of starch hydrolysate with one or more other components. Of the numerous starch hydrolysates known in the art, the invention finds particular applicability in connection with malto-oligosaccharides, which include maltodextrins and syrup solids. More generally, by xe2x80x9cmalto-oligosaccharidesxe2x80x9d is contemplated any species comprising two or more saccharide units linked predominately via 1-4 glycoside linkages, and including maltodextrins and syrup solids. Those malto-oligosaccharides and mixtures of malto-oligosaccharides having a DE (dextrose equivalent) less than 20 are known as maltodextrins; malto-oligosaccharide mixtures having a greater DE are known as syrup solids.
Malto-oligosaccharides most typically are provided as mixtures of a plurality of individual malto-oligosaccharide species. In preferred embodiments, at least 50 percent of the saccharide units in the malto-oligosaccharide are linked via 1-4 linkages. More preferably, at least about 60 percent of the saccharide units are linked via 1-4 linkages; even more preferably, at least about 80 percent of the saccharide units are so linked. The malto-oligosaccharides may include saccharide species having an odd DP (degree of polymerization) value, and the DP profile of the malto-oligosaccharide mixture may be partially defined by a saccharide species having a DP value of 1, for example, dextrose or sorbitol. The mixture further may include other saccharide species or other components. The malto-oligosaccharide mixture may be a reduced malto-oligosaccharide mixture, as disclosed, for example, in copending international application Ser. No. PCT/US9901098, filed Jan. 19, 1999, which application designates the United States.
The invention is particularly applicable to malto-oligosaccharide species in which at least a portion of the malto-oligosaccharides in the mixture have a DP value greater than 5. Preferably, at least one of the malto-oligosaccharide species in the mixture has a DP value of 8 or more. More preferably, at least one species has a DP value of at least 10. For example, in preferred embodiments of the invention, at least 80 percent of the malto-oligosaccharide species in the mixture have a DP greater than 5, and at least 60 percent may have a DP greater than 8. In another embodiment, at least 80 percent of the malto-oligosaccharides species have a DP greater than 10. In some embodiments of the invention, the DP profile of the starting mixture is such that at least 75 percent of the malto-oligosaccharides species in the mixture have a DP greater than 5 and at least 40 percent of the species in the mixture have a DP greater than 10.
Suitable malto-oligosaccharides are sold as maltodextrins under the trademark MALTRIN(copyright) by Grain Processing Corporation of Muscatine, Iowa. The MALTRIN(copyright) maltodextrins are malto-oligosaccharide products, each product including a mixture of malto-oligosaccharide species and having a known typical DP profile. Suitable MALTRIN(copyright) maltodextrins that may be used in conjunction with the present invention include, for example, MALTRIN(copyright) M040, MALTRIN(copyright) M050, MALTRIN(copyright) M100, MALTRIN(copyright) M150, and MALTRIN(copyright) M180. Typical approximate DP profiles of the subject MALTRIN(copyright) maltodextrins are set forth in the following table (the DP profiles being approximate as indicated in the table):
Other suitable malto-oligosaccharides include other maltodextrins, such as MALTRIN(copyright) M440, MALTRIN(copyright) 510, MALTRIN(copyright) M550; MALTRIN(copyright) M580, an MALTRIN(copyright) M700, as well as corn syrup solids such as MALTRIN(copyright) M200 and MALTRIN(copyright) M250 (these having a DE  greater than 25). The invention is not limited to malto-oligosaccharides species, and indeed the invention is contemplated more generally to be applicable to other starch hydrolysates including, for example, starch hydrolysates derived from crude or cereal flour, such as wheat or corn flour.
In accordance with the invention, the starch hydrolysate is compacted under sufficient compaction pressure to provide a compacted starch hydrolysate that has a relatively reduced tendency to become sticky in the presence of ambient moisture. The starch hydrolysate may be compacted via any suitable means, but most preferably, the hydrolysate is compacted via roller compaction, pellet milling, or extrusion. The compaction pressure should be such as to provide a compacted product that has a relatively reduced tendency to become sticky relative to the pre-compacted starch hydrolysate. This pressure preferably ranges from about 500 to about 2000 psi, most preferably about 1500 psi. When roller compaction is employed, it is preferred that, not counting any moisture content of the starch hydrolysate, the starch hydrolysate is compacted in the absence or substantial absence of any liquid that is more volatile than water; more preferably, not counting native starch moisture, the starch is compacted under anhydrous conditions; and most preferably, the starch hydrolysate is compacted in the absence or substantial absence of any added liquid.
When pellet milling or extrusion is employed, it is generally contemplated that a liquid such as water or a lubricant will be added. Preferably, no liquid that is more volatile than water is added. In particular, in a pellet milling operation, the total moisture content (including native moisture present in the starch hydrolyzate) should range from about 4% to about 12% by weight of the starch hydrolysate (or by weight of the blend if an additional nutrient is added). More preferably, the total moisture content ranges from about 6% to about 10%, and even more preferably, the total moisture content ranges from about 7% to about 9%.
The xe2x80x9cstickinessxe2x80x9d or tackiness of the starch hydrolysate can be evaluated by any suitable method. In accordance with one such method, a 15 g sample is spread out on a Petri dish, and the dish is placed in a glass container with a saturated solution of salt water and held for one week. Stickiness can be observed and a score assigned as follows:
0=No observed change, no stickiness.
1=Slight sticking of particles.
2=Obvious sticking together, break apart.
3=Particles sticking together, do not flow.
4=Almost melted appearance, can still observe some particles.
5=Melted, flowed together, lack of distinct particles.
The invention further encompasses a method for transporting a starch hydrolysate. In accordance with this aspect of the invention, the starch hydrolysate is compacted as discussed above, preferably in the absence or substantial absence of other ingredients except optionally a lubricant to aid in compaction, and the compacted starch hydrolysate then is transported. Most preferably, the starch hydrolysate is reduced to particles of a size suitable for transport and bulk conveyance, which typically is a size in the range of about 4 mesh to about 14 mesh. If the starch hydrolysate is compacted via roller compaction or extrusion, the compacted starch hydrolysate initially will be in the form of a larger agglomerated mass, and a subsequent processing step such as granulation should be employed to reduce the starch hydrolysate to particles. If pellet milling is employed, the pellets produced by the mill may be of a suitable size, but more commonly, the pellets will require crumbling to reduce them to a suitable size. The starch hydrolysate is particularly suitable for bulk transport, such as via rail car or truck. Because the starch hydrolysate will have a relatively reduced tendency to compress and to become sticky in the presence of ambient moisture, agglomeration of the starch hydrolysate particles and related problems generally associated with bulk transport of starch hydrolysates may be substantially mitigated.
The compacted starch hydrolysate may be used in numerous applications, including feed, food, and pharmaceutical applications including dry mix products, such as beverages, spice blends, sauces, gravies, and sports bars. Most particularly, the invention finds applicability in the field of feeds for cattle, swine, poultry birds, such as chickens, geese, and turkeys. In accordance with this aspect of the invention, a method for feeding a poultry bird is provided. Generally, the method includes the steps of providing a compacted starch hydrolysate, and feeding the compacted starch hydrolysate to a poultry bird. The compacted starch hydrolysate provides a dense, readily digestible carbohydrate that retains good transport handling properties when exposed to elevated humidity levels and increased compression forces experienced during bulk storage and conveyance. Most preferably, the poultry feed includes additional poultry nutrients, such as proteins, vitamins, minerals, and other carbohydrates. The invention is contemplated to encompass a poultry feed that comprises a compacted blend of the starch hydrolysate and the additional poultry nutrient. Such poultry feed may be prepared by blending the starch hydrolysate with the additional poultry nutrient, and compacting the resultant blend as discussed above.